Processes for the preparation of collagen-based materials for use in human and veterinary medicine by drying or lyophilizing aqueous collagen dispersions to create membranes or sponges are well known in the art. The use of collagen-based films or membranes as temporary, biodegradable barriers for separating apposing traumatized tissue surfaces following surgery to prevent or reduce the formation of postoperative adhesions is also known.
Typically, the collagen used for subsequent manufacture of the collagen-based materials is first isolated by extraction from mammalian hide or tendon, purified, enzymatically-treated to remove the non-helical telopeptides, partially solubilised with acid, and finally precipitated by increasing the pH to provide an aqueous dispersion of purified, fibrillar collagen. Once isolated, the collagen dispersion may be further processed for the manufacture of collagen-based materials immediately, or is otherwise stored while waiting further processing. For storage convenience at commercial scale, the collagen dispersion is normally concentrated by removal of water using centrifugation to reduce bulk and thereby create a wet mass. The wet mass must be stored frozen to preserve the collagen and prevent bacterial growth. When needed for manufacture of collagen-based materials, the frozen collagen wet mass is typically thawed and redispersed. Whether the isolated collagen is used immediately or frozen and thawed as a wet mass, the collagen dispersion is generally viscous and difficult to process at commercial scale into collagen-based membranes or lyophilized sponges. What is needed is a method to reduce the viscosity of the collagen dispersion without further dilution, since reducing the collagen concentration in the dispersion will only increase the amount of water that must be removed on subsequent drying or lyophilizing, which is both inefficient and costly at commercial scale.
Therefore, the object of the present invention is to modify the isolated collagen in such a way as to reduce the viscosity of the dispersion, but without compromising the properties of the collagen-based materials made thereof. Preferably, a further object of the present invention is to modify the collagen in such a way as to reduce the viscosity of the dispersion and also improve the properties of a collagen membrane made thereof for use as a postoperative adhesion barrier.
These objects are solved according to the present invention by providing a modified collagen that facilitates the efficient manufacture of collagen-based materials at commercial scale and improves the potential effectiveness of those materials in the field of human and veterinary medicine.